General Motors Co. (GM) and Honda (7267) Motor Co. are teaming up in a renewed push to market clean vehicles, with the two automotive giants seeking to have cheaper power-making fuel cells and hydrogen tanks ready by 2020.

The partnership between the largest U.S. automaker and Tokyo-based Honda is to include exchanging engineers, joint use of research facilities and shared sourcing of parts and materials, they said yesterday. The goal is a common hydrogen powertrain to make the low-polluting vehicles more affordable, they said, without providing details about prices or investment.

"We're talking about a complete sharing of all of our respective intellectual properties on the subject," Steve Girsky, GM's vice chairman, said at a New York press conference. "The cost of such technology has not come down as far as it must to become more commercially viable."

The allure of hydrogen as a clean automotive fuel led carmakers including the former General Motors Corp. to predict a decade ago that millions of fuel-cell autos would be on the road by now. While a mass market for hydrogen cars may be another decade or more away, automakers continue to pursue the technology.

Toyota Motor Corp. (7203), which had a hydrogen-technology alliance with GM in the early 2000s, plans to release a fuel-cell sedan in 2015 that will be unveiled in November. Honda, Hyundai Motor Co. (005380) and Daimler AG (DAI)'s Mercedes-Benz also plan retail sales of hydrogen cars in 2015, and Bayerische Motoren Werke AG has said it plans to use Toyota's fuel-cell system.

Ford Motor Co. (F), Daimler and Nissan Motor Co. also announced plans in January to collaborate on hydrogen-vehicle research to introduce fuel-cell autos by 2017.

'Definitive Advantage'

Environmental rules in the U.S., Europe and Japan encourage automakers to sell vehicles that don't emit climate-warming gases. That has aided hybrid sales, led to lighter cars and smaller engines, and convinced Tesla Motors Inc. (TSLA) and Nissan to push high-volume sales of battery cars.

"Among all zero-CO2 emission technologies, fuel-cell electric vehicles have a definitive advantage with range and refueling time that is as good as conventional gasoline cars," Honda President Takanobu Ito said in a statement.

GM and Honda also said they'll jointly lobby for an expanded network of hydrogen fuel stations, now clustered in the U.S. in California.

Battery-electric cars such as Tesla's Model S and Nissan (7201)'s Leaf hatchback share technologies with fuel-cell cars, including similar electric motors to power the wheels, brakes that capture power when stopping, software and related electronics.

Electricity Source

The difference is the electricity source. Battery cars store it in large lithium-ion packs -- Tesla's weigh 1,000 pounds (454 kilograms). Fuel cells generate it in an electro-chemical reaction of hydrogen and air.

In a fuel cell, hydrogen gas passes through a stack of plastic membranes and metal plates -- like syrup soaking a tower of platinum-dusted pancakes -- to produce electricity.Because of the precious metals needed, fuel-cell stacks remain expensive, as do high-pressure hydrogen tanks. Prototypes have cost $1 million to make.

Toyota's hydrogen fuel-cell sedan will be "price competitive" with Tesla's $69,900 Model S,'' Chris Hostetter, U.S. group vice president for advanced product development, said in an interview last month, without elaborating.

Tetsuo Iwamura, Honda's executive vice president, said yesterday a more advanced version of the FCX Clarity fuel cell sedan it leases only in California will be sold in 2015, without elaborating.

Supportive Tone

The industry push for hydrogen coincides with a more supportive tone from federal regulators, who advocated policies favoring battery-powered cars and production of lithium-ion batteries during President Barack Obama's first term.

California, the primary U.S. market for fuel-cell vehicles, is expanding its station network.The California Energy Commission awarded $18.7 million on June 12 to open as many as seven new hydrogen stations in the state, which now has just nine. About a dozen more are also in development, and the state's goal is to have at least 68 public hydrogen stations by 2017.